<?php    
// Configuration - Your Options       
$allowed_filetypes = array('.jpg','.gif','.bmp','.png'); 
// These will be the types of file that will pass the validation.       
$max_filesize = 524288; // Maximum filesize in BYTES (currently 0.5MB).       
$upload_path = './files/'; // The place the files will be uploaded to (currently a 'files' directory).      
$filename = $_FILES['userfile']['name']; // Get the name of the file (including file extension).    
$ext = substr($filename, strpos($filename,'.'), strlen($filename)-1); // Get the extension from the filename.      
// Check if the filetype is allowed, if not DIE and inform the user.    
if(!in_array($ext,$allowed_filetypes))       
	die('The file you attempted to upload is not allowed.');      
// Now check the filesize, if it is too large then DIE and inform the user.    
if(filesize($_FILES['userfile']['tmp_name']) > $max_filesize)       
	die('The file you attempted to upload is too large.');      
// Check if we can upload to the specified path, if not DIE and inform the user.    
if(!is_writable($upload_path))       
	die('You cannot upload to the specified directory, please CHMOD it to 777.');      
// We'll start handling the upload in the next step   
?>